7. ABSTRACT Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in the United States. Medically underserved populations experience a disproportionate burden of CRC mortality. Fecal occult blood test (FOBT) is a simple, easy to do, and widely accessible screening modality that helps to diminish CRC mortality disparities. The effectiveness of FOBT to reduce CRC mortality depends heavily on adherence to annual testing. Unfortunately, repeat FOBT screening ranges from 14% to 44%. A novel approach to encourage repeat annual FOBT is a technology-driven low cost mobile health (mHealth) educational intervention. mHealth interventions have been shown to lead to behavior change in a variety diseases; however its use to facilitate annual CRC screening (CRCS) with FOBT has not been studied. There is a timely opportunity to promote repeat annual FOBT screening in an existing cohort of medically underserved men and women enrolled in a trial to increase initial uptake of fecal immunochemical test (FIT), a type of FOBT, at community based clinics. Assessment of repeat FIT is beyond the scope of the parent trial, but repeat FIT uptake is expected to be low. The subject of this application is to explore the efficacy of an innovative, low cost, educational, evidence-based and theory-based mHealth intervention to promote adherence to annual FIT in a medically underserved population. During Phase I, a series of educational, targeted, and actionable mHealth messages will be developed and refined. This will be achieved by iterative focus groups and mobile technology testing and troubleshooting with (n=35) patients seen in community clinics. During Phase II, the feasibility, acceptability and preliminary efficacy of the Wired for CRCS intervention to educate and prompt patients to repeat CRCS with FIT will be assessed. To achieve this, 120 members of the existing cohort of men and women who are not up to date on annual FIT will be recruited and randomized to the Wired for CRCS intervention arm or usual care arm. Those randomized to the Wired for CRCS intervention will receive a series of educational, targeted, and actionable messages (refined during Phase I) on their cell phone. FIT uptake will be assessed four months after baseline. It is expected that the Wired for CRCS intervention will result in greater FIT uptake compared to usual care. Successful completion of this research will provide preliminary information on feasibility, acceptability, efficacy, usability and utility of a technology solution for promoting repeat annual FIT in a diverse sample of patients at community clinics. With this evidence, the team will be poised for a larger trial expected to provide a more definitive test of educational mHealth interventions on adherence to CRCS with annual FIT.